define('backbone/1.1.0/backbone-debug', ['_', '$'], function(require, exports) {

	var previousUnderscore = this._;
	var previousJQuery = this.jQuery;
	this._ = require('_');
	this.jQuery = require('$');

//     Backbone.js 1.1.0

//     (c) 2010-2011 Jeremy Ashkenas, DocumentCloud Inc.
//     (c) 2011-2013 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
//     Backbone may be freely distributed under the MIT license.
//     For all details and documentation:
//     http://backbonejs.org

	(function(){

		// Initial Setup
		// -------------

		// Save a reference to the global object (`window` in the browser, `exports`
		// on the server).
		var root = this;

		// Save the previous value of the `Backbone` variable, so that it can be
		// restored later on, if `noConflict` is used.
		var previousBackbone = root.Backbone;

		// Create local references to array methods we'll want to use later.
		var array = [];
		var push = array.push;
		var slice = array.slice;
		var splice = array.splice;

		// The top-level namespace. All public Backbone classes and modules will
		// be attached to this. Exported for both the browser and the server.
		var Backbone;
		if (typeof exports !== 'undefined') {
			Backbone = exports;
		} else {
			Backbone = root.Backbone = {};
		}

		// Current version of the library. Keep in sync with `package.json`.
		Backbone.VERSION = '1.1.0';

		// Require Underscore, if we're on the server, and it's not already present.
		var _ = root._;
		if (!_ && (typeof require !== 'undefined')) _ = require('underscore');

		// For Backbone's purposes, jQuery, Zepto, Ender, or My Library (kidding) owns
		// the `$` variable.
		Backbone.$ = root.jQuery || root.Zepto || root.ender || root.$;

		// Runs Backbone.js in *noConflict* mode, returning the `Backbone` variable
		// to its previous owner. Returns a reference to this Backbone object.
		Backbone.noConflict = function() {
			root.Backbone = previousBackbone;
			return this;
		};

		// Turn on `emulateHTTP` to support legacy HTTP servers. Setting this option
		// will fake `"PATCH"`, `"PUT"` and `"DELETE"` requests via the `_method` parameter and
		// set a `X-Http-Method-Override` header.
		Backbone.emulateHTTP = false;

		// Turn on `emulateJSON` to support legacy servers that can't deal with direct
		// `application/json` requests ... will encode the body as
		// `application/x-www-form-urlencoded` instead and will send the model in a
		// form param named `model`.
		Backbone.emulateJSON = false;

		// Backbone.Events
		// ---------------

		// A module that can be mixed in to *any object* in order to provide it with
		// custom events. You may bind with `on` or remove with `off` callback
		// functions to an event; `trigger`-ing an event fires all callbacks in
		// succession.
		//
		//     var object = {};
		//     _.extend(object, Backbone.Events);
		//     object.on('expand', function(){ alert('expanded'); });
		//     object.trigger('expand');
		//
		var Events = Backbone.Events = {

			// Bind an event to a `callback` function. Passing `"all"` will bind
			// the callback to all events fired.
			on: function(name, callback, context) {
				if (!eventsApi(this, 'on', name, [callback, context]) || !callback) return this;
				this._events || (this._events = {});
				var events = this._events[name] || (this._events[name] = []);
				events.push({callback: callback, context: context, ctx: context || this});
				return this;
			},

			// Bind an event to only be triggered a single time. After the first time
			// the callback is invoked, it will be removed.
			once: function(name, callback, context) {
				if (!eventsApi(this, 'once', name, [callback, context]) || !callback) return this;
				var self = this;
				var once = _.once(function() {
					self.off(name, once);
					callback.apply(this, arguments);
				});
				once._callback = callback;
				return this.on(name, once, context);
			},

			// Remove one or many callbacks. If `context` is null, removes all
			// callbacks with that function. If `callback` is null, removes all
			// callbacks for the event. If `name` is null, removes all bound
			// callbacks for all events.
			off: function(name, callback, context) {
				var retain, ev, events, names, i, l, j, k;
				if (!this._events || !eventsApi(this, 'off', name, [callback, context])) return this;
				if (!name && !callback && !context) {
					this._events = {};
					return this;
				}
				names = name ? [name] : _.keys(this._events);
				for (i = 0, l = names.length; i < l; i++) {
					name = names[i];
					if (events = this._events[name]) {
						this._events[name] = retain = [];
						if (callback || context) {
							for (j = 0, k = events.length; j < k; j++) {
								ev = events[j];
								if ((callback && callback !== ev.callback && callback !== ev.callback._callback) ||
									(context && context !== ev.context)) {
									retain.push(ev);
								}
							}
						}
						if (!retain.length) delete this._events[name];
					}
				}

				return this;
			},

			// Trigger one or many events, firing all bound callbacks. Callbacks are
			// passed the same arguments as `trigger` is, apart from the event name
			// (unless you're listening on `"all"`, which will cause your callback to
			// receive the true name of the event as the first argument).
			trigger: function(name) {
				if (!this._events) return this;
				var args = slice.call(arguments, 1);
				if (!eventsApi(this, 'trigger', name, args)) return this;
				var events = this._events[name];
				var allEvents = this._events.all;
				if (events) triggerEvents(events, args);
				if (allEvents) triggerEvents(allEvents, arguments);
				return this;
			},

			// Tell this object to stop listening to either specific events ... or
			// to every object it's currently listening to.
			stopListening: function(obj, name, callback) {
				var listeningTo = this._listeningTo;
				if (!listeningTo) return this;
				var remove = !name && !callback;
				if (!callback && typeof name === 'object') callback = this;
				if (obj) (listeningTo = {})[obj._listenId] = obj;
				for (var id in listeningTo) {
					obj = listeningTo[id];
					obj.off(name, callback, this);
					if (remove || _.isEmpty(obj._events)) delete this._listeningTo[id];
				}
				return this;
			}

		};

		// Regular expression used to split event strings.
		var eventSplitter = /\s+/;

		// Implement fancy features of the Events API such as multiple event
		// names `"change blur"` and jQuery-style event maps `{change: action}`
		// in terms of the existing API.
		var eventsApi = function(obj, action, name, rest) {
			if (!name) return true;

			// Handle event maps.
			if (typeof name === 'object') {
				for (var key in name) {
					obj[action].apply(obj, [key, name[key]].concat(rest));
				}
				return false;
			}

			// Handle space separated event names.
			if (eventSplitter.test(name)) {
				var names = name.split(eventSplitter);
				for (var i = 0, l = names.length; i < l; i++) {
					obj[action].apply(obj, [names[i]].concat(rest));
				}
				return false;
			}

			return true;
		};

		// A difficult-to-believe, but optimized internal dispatch function for
		// triggering events. Tries to keep the usual cases speedy (most internal
		// Backbone events have 3 arguments).
		var triggerEvents = function(events, args) {
			var ev, i = -1, l = events.length, a1 = args[0], a2 = args[1], a3 = args[2];
			switch (args.length) {
				case 0: while (++i < l) (ev = events[i]).callback.call(ev.ctx); return;
				case 1: while (++i < l) (ev = events[i]).callback.call(ev.ctx, a1); return;
				case 2: while (++i < l) (ev = events[i]).callback.call(ev.ctx, a1, a2); return;
				case 3: while (++i < l) (ev = events[i]).callback.call(ev.ctx, a1, a2, a3); return;
				default: while (++i < l) (ev = events[i]).callback.apply(ev.ctx, args);
			}
		};

		var listenMethods = {listenTo: 'on', listenToOnce: 'once'};

		// Inversion-of-control versions of `on` and `once`. Tell *this* object to
		// listen to an event in another object ... keeping track of what it's
		// listening to.
		_.each(listenMethods, function(implementation, method) {
			Events[method] = function(obj, name, callback) {
				var listeningTo = this._listeningTo || (this._listeningTo = {});
				var id = obj._listenId || (obj._listenId = _.uniqueId('l'));
				listeningTo[id] = obj;
				if (!callback && typeof name === 'object') callback = this;
				obj[implementation](name, callback, this);
				return this;
			};
		});

		// Aliases for backwards compatibility.
		Events.bind   = Events.on;
		Events.unbind = Events.off;

		// Allow the `Backbone` object to serve as a global event bus, for folks who
		// want global "pubsub" in a convenient place.
		_.extend(Backbone, Events);

		// Backbone.Model
		// --------------

		// Backbone **Models** are the basic data object in the framework --
		// frequently representing a row in a table in a database on your server.
		// A discrete chunk of data and a bunch of useful, related methods for
		// performing computations and transformations on that data.

		// Create a new model with the specified attributes. A client id (`cid`)
		// is automatically generated and assigned for you.
		var Model = Backbone.Model = function(attributes, options) {
			var attrs = attributes || {};
			options || (options = {});
			this.cid = _.uniqueId('c');
			this.attributes = {};
			if (options.collection) this.collection = options.collection;
			if (options.parse) attrs = this.parse(attrs, options) || {};
			attrs = _.defaults({}, attrs, _.result(this, 'defaults'));
			this.set(attrs, options);
			this.changed = {};
			this.initialize.apply(this, arguments);
		};

		// Attach all inheritable methods to the Model prototype.
		_.extend(Model.prototype, Events, {

			// A hash of attributes whose current and previous value differ.
			changed: null,

			// The value returned during the last failed validation.
			validationError: null,

			// The default name for the JSON `id` attribute is `"id"`. MongoDB and
			// CouchDB users may want to set this to `"_id"`.
			idAttribute: 'id',

			// Initialize is an empty function by default. Override it with your own
			// initialization logic.
			initialize: function(){},

			// Return a copy of the model's `attributes` object.
			toJSON: function(options) {
				return _.clone(this.attributes);
			},

			// Proxy `Backbone.sync` by default -- but override this if you need
			// custom syncing semantics for *this* particular model.
			sync: function() {
				return Backbone.sync.apply(this, arguments);
			},

			// Get the value of an attribute.
			get: function(attr) {
				return this.attributes[attr];
			},

			// Get the HTML-escaped value of an attribute.
			escape: function(attr) {
				return _.escape(this.get(attr));
			},

			// Returns `true` if the attribute contains a value that is not null
			// or undefined.
			has: function(attr) {
				return this.get(attr) != null;
			},

			// Set a hash of model attributes on the object, firing `"change"`. This is
			// the core primitive operation of a model, updating the data and notifying
			// anyone who needs to know about the change in state. The heart of the beast.
			set: function(key, val, options) {
				var attr, attrs, unset, changes, silent, changing, prev, current;
				if (key == null) return this;

				// Handle both `"key", value` and `{key: value}` -style arguments.
				if (typeof key === 'object') {
					attrs = key;
					options = val;
				} else {
					(attrs = {})[key] = val;
				}

				options || (options = {});

				// Run validation.
				if (!this._validate(attrs, options)) return false;

				// Extract attributes and options.
				unset           = options.unset;
				silent          = options.silent;
				changes         = [];
				changing        = this._changing;
				this._changing  = true;

				if (!changing) {
					this._previousAttributes = _.clone(this.attributes);
					this.changed = {};
				}
				current = this.attributes, prev = this._previousAttributes;

				// Check for changes of `id`.
				if (this.idAttribute in attrs) this.id = attrs[this.idAttribute];

				// For each `set` attribute, update or delete the current value.
				for (attr in attrs) {
					val = attrs[attr];
					if (!_.isEqual(current[attr], val)) changes.push(attr);
					if (!_.isEqual(prev[attr], val)) {
						this.changed[attr] = val;
					} else {
						delete this.changed[attr];
					}
					unset ? delete current[attr] : current[attr] = val;
				}

				// Trigger all relevant attribute changes.
				if (!silent) {
					if (changes.length) this._pending = true;
					for (var i = 0, l = changes.length; i < l; i++) {
						this.trigger('change:' + changes[i], this, current[changes[i]], options);
					}
				}

				// You might be wondering why there's a `while` loop here. Changes can
				// be recursively nested within `"change"` events.
				if (changing) return this;
				if (!silent) {
					while (this._pending) {
						this._pending = false;
						this.trigger('change', this, options);
					}
				}
				this._pending = false;
				this._changing = false;
				return this;
			},

			// Remove an attribute from the model, firing `"change"`. `unset` is a noop
			// if the attribute doesn't exist.
			unset: function(attr, options) {
				return this.set(attr, void 0, _.extend({}, options, {unset: true}));
			},

			// Clear all attributes on the model, firing `"change"`.
			clear: function(options) {
				var attrs = {};
				for (var key in this.attributes) attrs[key] = void 0;
				return this.set(attrs, _.extend({}, options, {unset: true}));
			},

			// Determine if the model has changed since the last `"change"` event.
			// If you specify an attribute name, determine if that attribute has changed.
			hasChanged: function(attr) {
				if (attr == null) return !_.isEmpty(this.changed);
				return _.has(this.changed, attr);
			},

			// Return an object containing all the attributes that have changed, or
			// false if there are no changed attributes. Useful for determining what
			// parts of a view need to be updated and/or what attributes need to be
			// persisted to the server. Unset attributes will be set to undefined.
			// You can also pass an attributes object to diff against the model,
			// determining if there *would be* a change.
			changedAttributes: function(diff) {
				if (!diff) return this.hasChanged() ? _.clone(this.changed) : false;
				var val, changed = false;
				var old = this._changing ? this._previousAttributes : this.attributes;
				for (var attr in diff) {
					if (_.isEqual(old[attr], (val = diff[attr]))) continue;
					(changed || (changed = {}))[attr] = val;
				}
				return changed;
			},

			// Get the previous value of an attribute, recorded at the time the last
			// `"change"` event was fired.
			previous: function(attr) {
				if (attr == null || !this._previousAttributes) return null;
				return this._previousAttributes[attr];
			},

			// Get all of the attributes of the model at the time of the previous
			// `"change"` event.
			previousAttributes: function() {
				return _.clone(this._previousAttributes);
			},

			// Fetch the model from the server. If the server's representation of the
			// model differs from its current attributes, they will be overridden,
			// triggering a `"change"` event.
			fetch: function(options) {
				options = options ? _.clone(options) : {};
				if (options.parse === void 0) options.parse = true;
				var model = this;
				var success = options.success;
				options.success = function(resp) {
					if (!model.set(model.parse(resp, options), options)) return false;
					if (success) success(model, resp, options);
					model.trigger('sync', model, resp, options);
				};
				wrapError(this, options);
				return this.sync('read', this, options);
			},

			// Set a hash of model attributes, and sync the model to the server.
			// If the server returns an attributes hash that differs, the model's
			// state will be `set` again.
			save: function(key, val, options) {
				var attrs, method, xhr, attributes = this.attributes;

				// Handle both `"key", value` and `{key: value}` -style arguments.
				if (key == null || typeof key === 'object') {
					attrs = key;
					options = val;
				} else {
					(attrs = {})[key] = val;
				}

				options = _.extend({validate: true}, options);

				// If we're not waiting and attributes exist, save acts as
				// `set(attr).save(null, opts)` with validation. Otherwise, check if
				// the model will be valid when the attributes, if any, are set.
				if (attrs && !options.wait) {
					if (!this.set(attrs, options)) return false;
				} else {
					if (!this._validate(attrs, options)) return false;
				}

				// Set temporary attributes if `{wait: true}`.
				if (attrs && options.wait) {
					this.attributes = _.extend({}, attributes, attrs);
				}

				// After a successful server-side save, the client is (optionally)
				// updated with the server-side state.
				if (options.parse === void 0) options.parse = true;
				var model = this;
				var success = options.success;
				options.success = function(resp) {
					// Ensure attributes are restored during synchronous saves.
					model.attributes = attributes;
					var serverAttrs = model.parse(resp, options);
					if (options.wait) serverAttrs = _.extend(attrs || {}, serverAttrs);
					if (_.isObject(serverAttrs) && !model.set(serverAttrs, options)) {
						return false;
					}
					if (success) success(model, resp, options);
					model.trigger('sync', model, resp, options);
				};
				wrapError(this, options);

				method = this.isNew() ? 'create' : (options.patch ? 'patch' : 'update');
				if (method === 'patch') options.attrs = attrs;
				xhr = this.sync(method, this, options);

				// Restore attributes.
				if (attrs && options.wait) this.attributes = attributes;

				return xhr;
			},

			// Destroy this model on the server if it was already persisted.
			// Optimistically removes the model from its collection, if it has one.
			// If `wait: true` is passed, waits for the server to respond before removal.
			destroy: function(options) {
				options = options ? _.clone(options) : {};
				var model = this;
				var success = options.success;

				var destroy = function() {
					model.trigger('destroy', model, model.collection, options);
				};

				options.success = function(resp) {
					if (options.wait || model.isNew()) destroy();
					if (success) success(model, resp, options);
					if (!model.isNew()) model.trigger('sync', model, resp, options);
				};

				if (this.isNew()) {
					options.success();
					return false;
				}
				wrapError(this, options);

				var xhr = this.sync('delete', this, options);
				if (!options.wait) destroy();
				return xhr;
			},

			// Default URL for the model's representation on the server -- if you're
			// using Backbone's restful methods, override this to change the endpoint
			// that will be called.
			url: function() {
				var base = _.result(this, 'urlRoot') || _.result(this.collection, 'url') || urlError();
				if (this.isNew()) return base;
				return base + (base.charAt(base.length - 1) === '/' ? '' : '/') + encodeURIComponent(this.id);
			},

			// **parse** converts a response into the hash of attributes to be `set` on
			// the model. The default implementation is just to pass the response along.
			parse: function(resp, options) {
				return resp;
			},

			// Create a new model with identical attributes to this one.
			clone: function() {
				return new this.constructor(this.attributes);
			},

			// A model is new if it has never been saved to the server, and lacks an id.
			isNew: function() {
				return this.id == null;
			},

			// Check if the model is currently in a valid state.
			isValid: function(options) {
				return this._validate({}, _.extend(options || {}, { validate: true }));
			},

			// Run validation against the next complete set of model attributes,
			// returning `true` if all is well. Otherwise, fire an `"invalid"` event.
			_validate: function(attrs, options) {
				if (!options.validate && !this.validate) return true;
				attrs = _.extend({}, this.attributes, attrs);
				var error = this.validationError = this.validate(attrs, options) || null;
				if (!error) return true;
				this.trigger('invalid', this, error, _.extend(options, {validationError: error}));
				return false;
			}

		});

		// Underscore methods that we want to implement on the Model.
		var modelMethods = ['keys', 'values', 'pairs', 'invert', 'pick', 'omit'];

		// Mix in each Underscore method as a proxy to `Model#attributes`.
		_.each(modelMethods, function(method) {
			Model.prototype[method] = function() {
				var args = slice.call(arguments);
				args.unshift(this.attributes);
				return _[method].apply(_, args);
			};
		});

		// Backbone.Collection
		// -------------------

		// If models tend to represent a single row of data, a Backbone Collection is
		// more analagous to a table full of data ... or a small slice or page of that
		// table, or a collection of rows that belong together for a particular reason
		// -- all of the messages in this particular folder, all of the documents
		// belonging to this particular author, and so on. Collections maintain
		// indexes of their models, both in order, and for lookup by `id`.

		// Create a new **Collection**, perhaps to contain a specific type of `model`.
		// If a `comparator` is specified, the Collection will maintain
		// its models in sort order, as they're added and removed.
		var Collection = Backbone.Collection = function(models, options) {
			options || (options = {});
			if (options.model) this.model = options.model;
			if (options.comparator !== void 0) this.comparator = options.comparator;
			this._reset();
			this.initialize.apply(this, arguments);
			if (models) this.reset(models, _.extend({silent: true}, options));
		};

		// Default options for `Collection#set`.
		var setOptions = {add: true, remove: true, merge: true};
		var addOptions = {add: true, remove: false};

		// Define the Collection's inheritable methods.
		_.extend(Collection.prototype, Events, {

			// The default model for a collection is just a **Backbone.Model**.
			// This should be overridden in most cases.
			model: Model,

			// Initialize is an empty function by default. Override it with your own
			// initialization logic.
			initialize: function(){},

			// The JSON representation of a Collection is an array of the
			// models' attributes.
			toJSON: function(options) {
				return this.map(function(model){ return model.toJSON(options); });
			},

			// Proxy `Backbone.sync` by default.
			sync: function() {
				return Backbone.sync.apply(this, arguments);
			},

			// Add a model, or list of models to the set.
			add: function(models, options) {
				return this.set(models, _.extend({merge: false}, options, addOptions));
			},

			// Remove a model, or a list of models from the set.
			remove: function(models, options) {
				var singular = !_.isArray(models);
				models = singular ? [models] : _.clone(models);
				options || (options = {});
				var i, l, index, model;
				for (i = 0, l = models.length; i < l; i++) {
					model = models[i] = this.get(models[i]);
					if (!model) continue;
					delete this._byId[model.id];
					delete this._byId[model.cid];
					index = this.indexOf(model);
					this.models.splice(index, 1);
					this.length--;
					if (!options.silent) {
						options.index = index;
						model.trigger('remove', model, this, options);
					}
					this._removeReference(model);
				}
				return singular ? models[0] : models;
			},

			// Update a collection by `set`-ing a new list of models, adding new ones,
			// removing models that are no longer present, and merging models that
			// already exist in the collection, as necessary. Similar to **Model#set**,
			// the core operation for updating the data contained by the collection.
			set: function(models, options) {
				options = _.defaults({}, options, setOptions);
				if (options.parse) models = this.parse(models, options);
				var singular = !_.isArray(models);
				models = singular ? (models ? [models] : []) : _.clone(models);
				var i, l, id, model, attrs, existing, sort;
				var at = options.at;
				var targetModel = this.model;
				var sortable = this.comparator && (at == null) && options.sort !== false;
				var sortAttr = _.isString(this.comparator) ? this.comparator : null;
				var toAdd = [], toRemove = [], modelMap = {};
				var add = options.add, merge = options.merge, remove = options.remove;
				var order = !sortable && add && remove ? [] : false;

				// Turn bare objects into model references, and prevent invalid models
				// from being added.
				for (i = 0, l = models.length; i < l; i++) {
					attrs = models[i];
					if (attrs instanceof Model) {
						id = model = attrs;
					} else {
						id = attrs[targetModel.prototype.idAttribute];
					}

					// If a duplicate is found, prevent it from being added and
					// optionally merge it into the existing model.
					if (existing = this.get(id)) {
						if (remove) modelMap[existing.cid] = true;
						if (merge) {
							attrs = attrs === model ? model.attributes : attrs;
							if (options.parse) attrs = existing.parse(attrs, options);
							existing.set(attrs, options);
							if (sortable && !sort && existing.hasChanged(sortAttr)) sort = true;
						}
						models[i] = existing;

						// If this is a new, valid model, push it to the `toAdd` list.
					} else if (add) {
						model = models[i] = this._prepareModel(attrs, options);
						if (!model) continue;
						toAdd.push(model);

						// Listen to added models' events, and index models for lookup by
						// `id` and by `cid`.
						model.on('all', this._onModelEvent, this);
						this._byId[model.cid] = model;
						if (model.id != null) this._byId[model.id] = model;
					}
					if (order) order.push(existing || model);
				}

				// Remove nonexistent models if appropriate.
				if (remove) {
					for (i = 0, l = this.length; i < l; ++i) {
						if (!modelMap[(model = this.models[i]).cid]) toRemove.push(model);
					}
					if (toRemove.length) this.remove(toRemove, options);
				}

				// See if sorting is needed, update `length` and splice in new models.
				if (toAdd.length || (order && order.length)) {
					if (sortable) sort = true;
					this.length += toAdd.length;
					if (at != null) {
						for (i = 0, l = toAdd.length; i < l; i++) {
							this.models.splice(at + i, 0, toAdd[i]);
						}
					} else {
						if (order) this.models.length = 0;
						var orderedModels = order || toAdd;
						for (i = 0, l = orderedModels.length; i < l; i++) {
							this.models.push(orderedModels[i]);
						}
					}
				}

				// Silently sort the collection if appropriate.
				if (sort) this.sort({silent: true});

				// Unless silenced, it's time to fire all appropriate add/sort events.
				if (!options.silent) {
					for (i = 0, l = toAdd.length; i < l; i++) {
						(model = toAdd[i]).trigger('add', model, this, options);
					}
					if (sort || (order && order.length)) this.trigger('sort', this, options);
				}

				// Return the added (or merged) model (or models).
				return singular ? models[0] : models;
			},

			// When you have more items than you want to add or remove individually,
			// you can reset the entire set with a new list of models, without firing
			// any granular `add` or `remove` events. Fires `reset` when finished.
			// Useful for bulk operations and optimizations.
			reset: function(models, options) {
				options || (options = {});
				for (var i = 0, l = this.models.length; i < l; i++) {
					this._removeReference(this.models[i]);
				}
				options.previousModels = this.models;
				this._reset();
				models = this.add(models, _.extend({silent: true}, options));
				if (!options.silent) this.trigger('reset', this, options);
				return models;
			},

			// Add a model to the end of the collection.
			push: function(model, options) {
				return this.add(model, _.extend({at: this.length}, options));
			},

			// Remove a model from the end of the collection.
			pop: function(options) {
				var model = this.at(this.length - 1);
				this.remove(model, options);
				return model;
			},

			// Add a model to the beginning of the collection.
			unshift: function(model, options) {
				return this.add(model, _.extend({at: 0}, options));
			},

			// Remove a model from the beginning of the collection.
			shift: function(options) {
				var model = this.at(0);
				this.remove(model, options);
				return model;
			},

			// Slice out a sub-array of models from the collection.
			slice: function() {
				return slice.apply(this.models, arguments);
			},

			// Get a model from the set by id.
			get: function(obj) {
				if (obj == null) return void 0;
				return this._byId[obj.id] || this._byId[obj.cid] || this._byId[obj];
			},

			// Get the model at the given index.
			at: function(index) {
				return this.models[index];
			},

			// Return models with matching attributes. Useful for simple cases of
			// `filter`.
			where: function(attrs, first) {
				if (_.isEmpty(attrs)) return first ? void 0 : [];
				return this[first ? 'find' : 'filter'](function(model) {
					for (var key in attrs) {
						if (attrs[key] !== model.get(key)) return false;
					}
					return true;
				});
			},

			// Return the first model with matching attributes. Useful for simple cases
			// of `find`.
			findWhere: function(attrs) {
				return this.where(attrs, true);
			},

			// Force the collection to re-sort itself. You don't need to call this under
			// normal circumstances, as the set will maintain sort order as each item
			// is added.
			sort: function(options) {
				if (!this.comparator) throw new Error('Cannot sort a set without a comparator');
				options || (options = {});

				// Run sort based on type of `comparator`.
				if (_.isString(this.comparator) || this.comparator.length === 1) {
					this.models = this.sortBy(this.comparator, this);
				} else {
					this.models.sort(_.bind(this.comparator, this));
				}

				if (!options.silent) this.trigger('sort', this, options);
				return this;
			},

			// Pluck an attribute from each model in the collection.
			pluck: function(attr) {
				return _.invoke(this.models, 'get', attr);
			},

			// Fetch the default set of models for this collection, resetting the
			// collection when they arrive. If `reset: true` is passed, the response
			// data will be passed through the `reset` method instead of `set`.
			fetch: function(options) {
				options = options ? _.clone(options) : {};
				if (options.parse === void 0) options.parse = true;
				var success = options.success;
				var collection = this;
				options.success = function(resp) {
					var method = options.reset ? 'reset' : 'set';
					collection[method](resp, options);
					if (success) success(collection, resp, options);
					collection.trigger('sync', collection, resp, options);
				};
				wrapError(this, options);
				return this.sync('read', this, options);
			},

			// Create a new instance of a model in this collection. Add the model to the
			// collection immediately, unless `wait: true` is passed, in which case we
			// wait for the server to agree.
			create: function(model, options) {
				options = options ? _.clone(options) : {};
				if (!(model = this._prepareModel(model, options))) return false;
				if (!options.wait) this.add(model, options);
				var collection = this;
				var success = options.success;
				options.success = function(model, resp, options) {
					if (options.wait) collection.add(model, options);
					if (success) success(model, resp, options);
				};
				model.save(null, options);
				return model;
			},

			// **parse** converts a response into a list of models to be added to the
			// collection. The default implementation is just to pass it through.
			parse: function(resp, options) {
				return resp;
			},

			// Create a new collection with an identical list of models as this one.
			clone: function() {
				return new this.constructor(this.models);
			},

			// Private method to reset all internal state. Called when the collection
			// is first initialized or reset.
			_reset: function() {
				this.length = 0;
				this.models = [];
				this._byId  = {};
			},

			// Prepare a hash of attributes (or other model) to be added to this
			// collection.
			_prepareModel: function(attrs, options) {
				if (attrs instanceof Model) {
					if (!attrs.collection) attrs.collection = this;
					return attrs;
				}
				options = options ? _.clone(options) : {};
				options.collection = this;
				var model = new this.model(attrs, options);
				if (!model.validationError) return model;
				this.trigger('invalid', this, model.validationError, options);
				return false;
			},

			// Internal method to sever a model's ties to a collection.
			_removeReference: function(model) {
				if (this === model.collection) delete model.collection;
				model.off('all', this._onModelEvent, this);
			},

			// Internal method called every time a model in the set fires an event.
			// Sets need to update their indexes when models change ids. All other
			// events simply proxy through. "add" and "remove" events that originate
			// in other collections are ignored.
			_onModelEvent: function(event, model, collection, options) {
				if ((event === 'add' || event === 'remove') && collection !== this) return;
				if (event === 'destroy') this.remove(model, options);
				if (model && event === 'change:' + model.idAttribute) {
					delete this._byId[model.previous(model.idAttribute)];
					if (model.id != null) this._byId[model.id] = model;
				}
				this.trigger.apply(this, arguments);
			}

		});

		// Underscore methods that we want to implement on the Collection.
		// 90% of the core usefulness of Backbone Collections is actually implemented
		// right here:
		var methods = ['forEach', 'each', 'map', 'collect', 'reduce', 'foldl',
			'inject', 'reduceRight', 'foldr', 'find', 'detect', 'filter', 'select',
			'reject', 'every', 'all', 'some', 'any', 'include', 'contains', 'invoke',
			'max', 'min', 'toArray', 'size', 'first', 'head', 'take', 'initial', 'rest',
			'tail', 'drop', 'last', 'without', 'difference', 'indexOf', 'shuffle',
			'lastIndexOf', 'isEmpty', 'chain'];

		// Mix in each Underscore method as a proxy to `Collection#models`.
		_.each(methods, function(method) {
			Collection.prototype[method] = function() {
				var args = slice.call(arguments);
				args.unshift(this.models);
				return _[method].apply(_, args);
			};
		});

		// Underscore methods that take a property name as an argument.
		var attributeMethods = ['groupBy', 'countBy', 'sortBy'];

		// Use attributes instead of properties.
		_.each(attributeMethods, function(method) {
			Collection.prototype[method] = function(value, context) {
				var iterator = _.isFunction(value) ? value : function(model) {
					return model.get(value);
				};
				return _[method](this.models, iterator, context);
			};
		});

		// Backbone.View
		// -------------

		// Backbone Views are almost more convention than they are actual code. A View
		// is simply a JavaScript object that represents a logical chunk of UI in the
		// DOM. This might be a single item, an entire list, a sidebar or panel, or
		// even the surrounding frame which wraps your whole app. Defining a chunk of
		// UI as a **View** allows you to define your DOM events declaratively, without
		// having to worry about render order ... and makes it easy for the view to
		// react to specific changes in the state of your models.

		// Creating a Backbone.View creates its initial element outside of the DOM,
		// if an existing element is not provided...
		var View = Backbone.View = function(options) {
			this.cid = _.uniqueId('view');
			options || (options = {});
			_.extend(this, _.pick(options, viewOptions));
			this._ensureElement();
			this.initialize.apply(this, arguments);
			this.delegateEvents();
		};

		// Cached regex to split keys for `delegate`.
		var delegateEventSplitter = /^(\S+)\s*(.*)$/;

		// List of view options to be merged as properties.
		var viewOptions = ['model', 'collection', 'el', 'id', 'attributes', 'className', 'tagName', 'events'];

		// Set up all inheritable **Backbone.View** properties and methods.
		_.extend(View.prototype, Events, {

			// The default `tagName` of a View's element is `"div"`.
			tagName: 'div',

			// jQuery delegate for element lookup, scoped to DOM elements within the
			// current view. This should be preferred to global lookups where possible.
			$: function(selector) {
				return this.$el.find(selector);
			},

			// Initialize is an empty function by default. Override it with your own
			// initialization logic.
			initialize: function(){},

			// **render** is the core function that your view should override, in order
			// to populate its element (`this.el`), with the appropriate HTML. The
			// convention is for **render** to always return `this`.
			render: function() {
				return this;
			},

			// Remove this view by taking the element out of the DOM, and removing any
			// applicable Backbone.Events listeners.
			remove: function() {
				this.$el.remove();
				this.stopListening();
				return this;
			},

			// Change the view's element (`this.el` property), including event
			// re-delegation.
			setElement: function(element, delegate) {
				if (this.$el) this.undelegateEvents();
				this.$el = element instanceof Backbone.$ ? element : Backbone.$(element);
				this.el = this.$el[0];
				if (delegate !== false) this.delegateEvents();
				return this;
			},

			// Set callbacks, where `this.events` is a hash of
			//
			// *{"event selector": "callback"}*
			//
			//     {
			//       'mousedown .title':  'edit',
			//       'click .button':     'save',
			//       'click .open':       function(e) { ... }
			//     }
			//
			// pairs. Callbacks will be bound to the view, with `this` set properly.
			// Uses event delegation for efficiency.
			// Omitting the selector binds the event to `this.el`.
			// This only works for delegate-able events: not `focus`, `blur`, and
			// not `change`, `submit`, and `reset` in Internet Explorer.
			delegateEvents: function(events) {
				if (!(events || (events = _.result(this, 'events')))) return this;
				this.undelegateEvents();
				for (var key in events) {
					var method = events[key];
					if (!_.isFunction(method)) method = this[events[key]];
					if (!method) continue;

					var match = key.match(delegateEventSplitter);
					var eventName = match[1], selector = match[2];
					method = _.bind(method, this);
					eventName += '.delegateEvents' + this.cid;
					if (selector === '') {
						this.$el.on(eventName, method);
					} else {
						this.$el.on(eventName, selector, method);
					}
				}
				return this;
			},

			// Clears all callbacks previously bound to the view with `delegateEvents`.
			// You usually don't need to use this, but may wish to if you have multiple
			// Backbone views attached to the same DOM element.
			undelegateEvents: function() {
				this.$el.off('.delegateEvents' + this.cid);
				return this;
			},

			// Ensure that the View has a DOM element to render into.
			// If `this.el` is a string, pass it through `$()`, take the first
			// matching element, and re-assign it to `el`. Otherwise, create
			// an element from the `id`, `className` and `tagName` properties.
			_ensureElement: function() {
				if (!this.el) {
					var attrs = _.extend({}, _.result(this, 'attributes'));
					if (this.id) attrs.id = _.result(this, 'id');
					if (this.className) attrs['class'] = _.result(this, 'className');
					var $el = Backbone.$('<' + _.result(this, 'tagName') + '>').attr(attrs);
					this.setElement($el, false);
				} else {
					this.setElement(_.result(this, 'el'), false);
				}
			}

		});

		// Backbone.sync
		// -------------

		// Override this function to change the manner in which Backbone persists
		// models to the server. You will be passed the type of request, and the
		// model in question. By default, makes a RESTful Ajax request
		// to the model's `url()`. Some possible customizations could be:
		//
		// * Use `setTimeout` to batch rapid-fire updates into a single request.
		// * Send up the models as XML instead of JSON.
		// * Persist models via WebSockets instead of Ajax.
		//
		// Turn on `Backbone.emulateHTTP` in order to send `PUT` and `DELETE` requests
		// as `POST`, with a `_method` parameter containing the true HTTP method,
		// as well as all requests with the body as `application/x-www-form-urlencoded`
		// instead of `application/json` with the model in a param named `model`.
		// Useful when interfacing with server-side languages like **PHP** that make
		// it difficult to read the body of `PUT` requests.
		Backbone.sync = function(method, model, options) {
			var type = methodMap[method];

			// Default options, unless specified.
			_.defaults(options || (options = {}), {
				emulateHTTP: Backbone.emulateHTTP,
				emulateJSON: Backbone.emulateJSON
			});

			// Default JSON-request options.
			var params = {type: type, dataType: 'json'};

			// Ensure that we have a URL.
			if (!options.url) {
				params.url = _.result(model, 'url') || urlError();
			}

			// Ensure that we have the appropriate request data.
			if (options.data == null && model && (method === 'create' || method === 'update' || method === 'patch')) {
				params.contentType = 'application/json';
				params.data = JSON.stringify(options.attrs || model.toJSON(options));
			}

			// For older servers, emulate JSON by encoding the request into an HTML-form.
			if (options.emulateJSON) {
				params.contentType = 'application/x-www-form-urlencoded';
				params.data = params.data ? {model: params.data} : {};
			}

			// For older servers, emulate HTTP by mimicking the HTTP method with `_method`
			// And an `X-HTTP-Method-Override` header.
			if (options.emulateHTTP && (type === 'PUT' || type === 'DELETE' || type === 'PATCH')) {
				params.type = 'POST';
				if (options.emulateJSON) params.data._method = type;
				var beforeSend = options.beforeSend;
				options.beforeSend = function(xhr) {
					xhr.setRequestHeader('X-HTTP-Method-Override', type);
					if (beforeSend) return beforeSend.apply(this, arguments);
				};
			}

			// Don't process data on a non-GET request.
			if (params.type !== 'GET' && !options.emulateJSON) {
				params.processData = false;
			}

			// If we're sending a `PATCH` request, and we're in an old Internet Explorer
			// that still has ActiveX enabled by default, override jQuery to use that
			// for XHR instead. Remove this line when jQuery supports `PATCH` on IE8.
			if (params.type === 'PATCH' && noXhrPatch) {
				params.xhr = function() {
					return new ActiveXObject("Microsoft.XMLHTTP");
				};
			}

			// Make the request, allowing the user to override any Ajax options.
			var xhr = options.xhr = Backbone.ajax(_.extend(params, options));
			model.trigger('request', model, xhr, options);
			return xhr;
		};

		var noXhrPatch = typeof window !== 'undefined' && !!window.ActiveXObject && !(window.XMLHttpRequest && (new XMLHttpRequest).dispatchEvent);

		// Map from CRUD to HTTP for our default `Backbone.sync` implementation.
		var methodMap = {
			'create': 'POST',
			'update': 'PUT',
			'patch':  'PATCH',
			'delete': 'DELETE',
			'read':   'GET'
		};

		// Set the default implementation of `Backbone.ajax` to proxy through to `$`.
		// Override this if you'd like to use a different library.
		Backbone.ajax = function() {
			return Backbone.$.ajax.apply(Backbone.$, arguments);
		};

		// Backbone.Router
		// ---------------

		// Routers map faux-URLs to actions, and fire events when routes are
		// matched. Creating a new one sets its `routes` hash, if not set statically.
		var Router = Backbone.Router = function(options) {
			options || (options = {});
			if (options.routes) this.routes = options.routes;
			this._bindRoutes();
			this.initialize.apply(this, arguments);
		};

		// Cached regular expressions for matching named param parts and splatted
		// parts of route strings.
		var optionalParam = /\((.*?)\)/g;
		var namedParam    = /(\(\?)?:\w+/g;
		var splatParam    = /\*\w+/g;
		var escapeRegExp  = /[\-{}\[\]+?.,\\\^$|#\s]/g;

		// Set up all inheritable **Backbone.Router** properties and methods.
		_.extend(Router.prototype, Events, {

			// Initialize is an empty function by default. Override it with your own
			// initialization logic.
			initialize: function(){},

			// Manually bind a single named route to a callback. For example:
			//
			//     this.route('search/:query/p:num', 'search', function(query, num) {
			//       ...
			//     });
			//
			route: function(route, name, callback) {
				if (!_.isRegExp(route)) route = this._routeToRegExp(route);
				if (_.isFunction(name)) {
					callback = name;
					name = '';
				}
				if (!callback) callback = this[name];
				var router = this;
				Backbone.history.route(route, function(fragment) {
					var args = router._extractParameters(route, fragment);
					callback && callback.apply(router, args);
					router.trigger.apply(router, ['route:' + name].concat(args));
					router.trigger('route', name, args);
					Backbone.history.trigger('route', router, name, args);
				});
				return this;
			},

			// Simple proxy to `Backbone.history` to save a fragment into the history.
			navigate: function(fragment, options) {
				Backbone.history.navigate(fragment, options);
				return this;
			},

			// Bind all defined routes to `Backbone.history`. We have to reverse the
			// order of the routes here to support behavior where the most general
			// routes can be defined at the bottom of the route map.
			_bindRoutes: function() {
				if (!this.routes) return;
				this.routes = _.result(this, 'routes');
				var route, routes = _.keys(this.routes);
				while ((route = routes.pop()) != null) {
					this.route(route, this.routes[route]);
				}
			},

			// Convert a route string into a regular expression, suitable for matching
			// against the current location hash.
			_routeToRegExp: function(route) {
				route = route.replace(escapeRegExp, '\\$&')
					.replace(optionalParam, '(?:$1)?')
					.replace(namedParam, function(match, optional) {
						return optional ? match : '([^\/]+)';
					})
					.replace(splatParam, '(.*?)');
				return new RegExp('^' + route + '$');
			},

			// Given a route, and a URL fragment that it matches, return the array of
			// extracted decoded parameters. Empty or unmatched parameters will be
			// treated as `null` to normalize cross-browser behavior.
			_extractParameters: function(route, fragment) {
				var params = route.exec(fragment).slice(1);
				return _.map(params, function(param) {
					return param ? decodeURIComponent(param) : null;
				});
			}

		});

		// Backbone.History
		// ----------------

		// Handles cross-browser history management, based on either
		// [pushState](http://diveintohtml5.info/history.html) and real URLs, or
		// [onhashchange](https://developer.mozilla.org/en-US/docs/DOM/window.onhashchange)
		// and URL fragments. If the browser supports neither (old IE, natch),
		// falls back to polling.
		var History = Backbone.History = function() {
			this.handlers = [];
			_.bindAll(this, 'checkUrl');

			// Ensure that `History` can be used outside of the browser.
			if (typeof window !== 'undefined') {
				this.location = window.location;
				this.history = window.history;
			}
		};

		// Cached regex for stripping a leading hash/slash and trailing space.
		var routeStripper = /^[#\/]|\s+$/g;

		// Cached regex for stripping leading and trailing slashes.
		var rootStripper = /^\/+|\/+$/g;

		// Cached regex for detecting MSIE.
		var isExplorer = /msie [\w.]+/;

		// Cached regex for removing a trailing slash.
		var trailingSlash = /\/$/;

		// Cached regex for stripping urls of hash and query.
		var pathStripper = /[?#].*$/;

		// Has the history handling already been started?
		History.started = false;

		// Set up all inheritable **Backbone.History** properties and methods.
		_.extend(History.prototype, Events, {

			// The default interval to poll for hash changes, if necessary, is
			// twenty times a second.
			interval: 50,

			// Gets the true hash value. Cannot use location.hash directly due to bug
			// in Firefox where location.hash will always be decoded.
			getHash: function(window) {
				var match = (window || this).location.href.match(/#(.*)$/);
				return match ? match[1] : '';
			},

			// Get the cross-browser normalized URL fragment, either from the URL,
			// the hash, or the override.
			getFragment: function(fragment, forcePushState) {
				if (fragment == null) {
					if (this._hasPushState || !this._wantsHashChange || forcePushState) {
						fragment = this.location.pathname;
						var root = this.root.replace(trailingSlash, '');
						if (!fragment.indexOf(root)) fragment = fragment.slice(root.length);
					} else {
						fragment = this.getHash();
					}
				}
				return fragment.replace(routeStripper, '');
			},

			// Start the hash change handling, returning `true` if the current URL matches
			// an existing route, and `false` otherwise.
			start: function(options) {
				if (History.started) throw new Error("Backbone.history has already been started");
				History.started = true;

				// Figure out the initial configuration. Do we need an iframe?
				// Is pushState desired ... is it available?
				this.options          = _.extend({root: '/'}, this.options, options);
				this.root             = this.options.root;
				this._wantsHashChange = this.options.hashChange !== false;
				this._wantsPushState  = !!this.options.pushState;
				this._hasPushState    = !!(this.options.pushState && this.history && this.history.pushState);
				var fragment          = this.getFragment();
				var docMode           = document.documentMode;
				var oldIE             = (isExplorer.exec(navigator.userAgent.toLowerCase()) && (!docMode || docMode <= 7));

				// Normalize root to always include a leading and trailing slash.
				this.root = ('/' + this.root + '/').replace(rootStripper, '/');

				if (oldIE && this._wantsHashChange) {
					this.iframe = Backbone.$('<iframe src="javascript:0" tabindex="-1" />').hide().appendTo('body')[0].contentWindow;
					this.navigate(fragment);
				}

				// Depending on whether we're using pushState or hashes, and whether
				// 'onhashchange' is supported, determine how we check the URL state.
				if (this._hasPushState) {
					Backbone.$(window).on('popstate', this.checkUrl);
				} else if (this._wantsHashChange && ('onhashchange' in window) && !oldIE) {
					Backbone.$(window).on('hashchange', this.checkUrl);
				} else if (this._wantsHashChange) {
					this._checkUrlInterval = setInterval(this.checkUrl, this.interval);
				}

				// Determine if we need to change the base url, for a pushState link
				// opened by a non-pushState browser.
				this.fragment = fragment;
				var loc = this.location;
				var atRoot = loc.pathname.replace(/[^\/]$/, '$&/') === this.root;

				// Transition from hashChange to pushState or vice versa if both are
				// requested.
				if (this._wantsHashChange && this._wantsPushState) {

					// If we've started off with a route from a `pushState`-enabled
					// browser, but we're currently in a browser that doesn't support it...
					if (!this._hasPushState && !atRoot) {
						this.fragment = this.getFragment(null, true);
						this.location.replace(this.root + this.location.search + '#' + this.fragment);
						// Return immediately as browser will do redirect to new url
						return true;

						// Or if we've started out with a hash-based route, but we're currently
						// in a browser where it could be `pushState`-based instead...
					} else if (this._hasPushState && atRoot && loc.hash) {
						this.fragment = this.getHash().replace(routeStripper, '');
						this.history.replaceState({}, document.title, this.root + this.fragment + loc.search);
					}

				}

				if (!this.options.silent) return this.loadUrl();
			},

			// Disable Backbone.history, perhaps temporarily. Not useful in a real app,
			// but possibly useful for unit testing Routers.
			stop: function() {
				Backbone.$(window).off('popstate', this.checkUrl).off('hashchange', this.checkUrl);
				clearInterval(this._checkUrlInterval);
				History.started = false;
			},

			// Add a route to be tested when the fragment changes. Routes added later
			// may override previous routes.
			route: function(route, callback) {
				this.handlers.unshift({route: route, callback: callback});
			},

			// Checks the current URL to see if it has changed, and if it has,
			// calls `loadUrl`, normalizing across the hidden iframe.
			checkUrl: function(e) {
				var current = this.getFragment();
				if (current === this.fragment && this.iframe) {
					current = this.getFragment(this.getHash(this.iframe));
				}
				if (current === this.fragment) return false;
				if (this.iframe) this.navigate(current);
				this.loadUrl();
			},

			// Attempt to load the current URL fragment. If a route succeeds with a
			// match, returns `true`. If no defined routes matches the fragment,
			// returns `false`.
			loadUrl: function(fragment) {
				fragment = this.fragment = this.getFragment(fragment);
				return _.any(this.handlers, function(handler) {
					if (handler.route.test(fragment)) {
						handler.callback(fragment);
						return true;
					}
				});
			},

			// Save a fragment into the hash history, or replace the URL state if the
			// 'replace' option is passed. You are responsible for properly URL-encoding
			// the fragment in advance.
			//
			// The options object can contain `trigger: true` if you wish to have the
			// route callback be fired (not usually desirable), or `replace: true`, if
			// you wish to modify the current URL without adding an entry to the history.
			navigate: function(fragment, options) {
				if (!History.started) return false;
				if (!options || options === true) options = {trigger: !!options};

				var url = this.root + (fragment = this.getFragment(fragment || ''));

				// Strip the fragment of the query and hash for matching.
				fragment = fragment.replace(pathStripper, '');

				if (this.fragment === fragment) return;
				this.fragment = fragment;

				// Don't include a trailing slash on the root.
				if (fragment === '' && url !== '/') url = url.slice(0, -1);

				// If pushState is available, we use it to set the fragment as a real URL.
				if (this._hasPushState) {
					this.history[options.replace ? 'replaceState' : 'pushState']({}, document.title, url);

					// If hash changes haven't been explicitly disabled, update the hash
					// fragment to store history.
				} else if (this._wantsHashChange) {
					this._updateHash(this.location, fragment, options.replace);
					if (this.iframe && (fragment !== this.getFragment(this.getHash(this.iframe)))) {
						// Opening and closing the iframe tricks IE7 and earlier to push a
						// history entry on hash-tag change.  When replace is true, we don't
						// want this.
						if(!options.replace) this.iframe.document.open().close();
						this._updateHash(this.iframe.location, fragment, options.replace);
					}

					// If you've told us that you explicitly don't want fallback hashchange-
					// based history, then `navigate` becomes a page refresh.
				} else {
					return this.location.assign(url);
				}
				if (options.trigger) return this.loadUrl(fragment);
			},

			// Update the hash location, either replacing the current entry, or adding
			// a new one to the browser history.
			_updateHash: function(location, fragment, replace) {
				if (replace) {
					var href = location.href.replace(/(javascript:|#).*$/, '');
					location.replace(href + '#' + fragment);
				} else {
					// Some browsers require that `hash` contains a leading #.
					location.hash = '#' + fragment;
				}
			}

		});

		// Create the default Backbone.history.
		Backbone.history = new History;

		// Helpers
		// -------

		// Helper function to correctly set up the prototype chain, for subclasses.
		// Similar to `goog.inherits`, but uses a hash of prototype properties and
		// class properties to be extended.
		var extend = function(protoProps, staticProps) {
			var parent = this;
			var child;

			// The constructor function for the new subclass is either defined by you
			// (the "constructor" property in your `extend` definition), or defaulted
			// by us to simply call the parent's constructor.
			if (protoProps && _.has(protoProps, 'constructor')) {
				child = protoProps.constructor;
			} else {
				child = function(){ return parent.apply(this, arguments); };
			}

			// Add static properties to the constructor function, if supplied.
			_.extend(child, parent, staticProps);

			// Set the prototype chain to inherit from `parent`, without calling
			// `parent`'s constructor function.
			var Surrogate = function(){ this.constructor = child; };
			Surrogate.prototype = parent.prototype;
			child.prototype = new Surrogate;

			// Add prototype properties (instance properties) to the subclass,
			// if supplied.
			if (protoProps) _.extend(child.prototype, protoProps);

			// Set a convenience property in case the parent's prototype is needed
			// later.
			child.__super__ = parent.prototype;

			return child;
		};

		// Set up inheritance for the model, collection, router, view and history.
		Model.extend = Collection.extend = Router.extend = View.extend = History.extend = extend;

		// Throw an error when a URL is needed, and none is supplied.
		var urlError = function() {
			throw new Error('A "url" property or function must be specified');
		};

		// Wrap an optional error callback with a fallback error event.
		var wrapError = function(model, options) {
			var error = options.error;
			options.error = function(resp) {
				if (error) error(model, resp, options);
				model.trigger('error', model, resp, options);
			};
		};

	}).call(this);

	this._ = previousUnderscore;
	this.jQuery = previousJQuery;
});